CVE-2026-55517

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.5, a Deno program that opens a client WebSocket connection could be crashed by the remote server. While handling the WebSocket handshake response, Deno parsed the Sec-WebSocket-Protocol and Sec-WebSocket-Extensions response...

CVE-2026-49983

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, environment access is gated by the env permission. You can deny it with --deny-env, or restrict it to a specific allowlist with --allow-env=FOO,BAR. The expectation is that a program running without env permission cannot...

CVE-2026-49860

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when a WebSocket connection was opened, Deno checked the destination hostname against --deny-net rules but did not re-check the IP addresses that hostname resolved to. An attacker-controlled script could use a specially...

CVE-2026-49401

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.14, Deno's permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-ffi. On macOS, that comparison was done...

CVE-2026-49402

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.10, Deno's node:childprocess implementation provided an escapeShellArg helper used when callers passed shell: true to spawn / spawnSync / exec and friends. On Windows, the helper failed to quote arguments that contained cmd.e...

CVE-2026-49411

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.0, the Node.js compatibility TCP path checked the permission against the original hostname string before resolution and then did not re-check after resolution. A caller could therefore pass a numeric alias of an IP address fo...

CVE-2026-49859

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when fetch was called, Deno checked the destination hostname against --deny-net rules but did not re-check the IP addresses that hostname resolved to. An attacker-controlled script could use a specially crafted domain name...

CVE-2026-49406

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.12, when Deno was run in BYONM mode nodeModulesDir: "manual", the module resolver did not validate that a package's resolved entrypoint stayed within its nodemodules// directory. A malicious package.json whose main field...

CVE-2026-49440

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, node:crypto.checkPrimecandidate, options, callback and crypto.checkPrimeSynccandidate, options ran no Miller-Rabin rounds at all when the caller left options.checks at its default of 0. In that mode, the only test applied ...

CVE-2026-44726

Deno is a JavaScript, TypeScript, and WebAssembly runtime. From 2.0.0 until 2.7.8, a flaw in Deno's Node.js tls compatibility layer could cause a TLS client to transmit application data in plaintext after a connection retry. When autoSelectFamily was enabled and the first address-family attempt...

CVE-2026-55517

CVE-2026-55517 affects Deno prior to 2.7.5, where a client WebSocket handshake could crash the process if the server returned non-ASCII bytes in Sec-WebSocket-Protocol or Sec-WebSocket-Extensions headers. The root cause is parsing those headers as ASCII strings, triggering a panic when non-printa...

CVE-2026-55517 Deno: Denial of service via non-ASCII bytes in WebSocket response headers

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.5, a Deno program that opens a client WebSocket connection could be crashed by the remote server. While handling the WebSocket handshake response, Deno parsed the Sec-WebSocket-Protocol and Sec-WebSocket-Extensions response...

CVE-2026-44726

CVE-2026-44726 affects Deno (2.0.0–2.7.8) via the Node.js tls compatibility layer. When autoSelectFamily is enabled and the first address-family attempt fails, the socket reinitialization path reuses a stale TLS upgrade hook tied to the original failed handle, causing the replacement TCP connecti...

CVE-2026-49401

CVE-2026-49401 describes a permission bypass in Deno on macOS APFS prior to v2.7.14. The denial checks for --deny-read/--deny-write/--deny-run/--deny-ffi were performed at the raw-byte level, but APFS considers different Unicode spellings of the same name as the same file. This allowed a process ...

CVE-2026-49401 Deno Permission Bypass via Unicode Normalization Mismatch on macOS (APFS)

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.14, Deno's permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-ffi. On macOS, that comparison was done...

CVE-2026-49402

Deno is affected by CVE-2026-49402 on Windows when using node:child_process with shell: true. The escapeShellArg() helper failed to properly quote arguments containing cmd.exe metacharacters (e.g., &, |, , ^, !, (, )), and did not neutralize % inside double-quoted strings. This allowed an attacke...

CVE-2026-49402 Deno: Command Injection via spawnSync & spawn on Windows

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.10, Deno's node:childprocess implementation provided an escapeShellArg helper used when callers passed shell: true to spawn / spawnSync / exec and friends. On Windows, the helper failed to quote arguments that contained cmd.e...

CVE-2026-49406

The CVE describes a vulnerability in Deno when run in BYONM mode (nodeModulesDir: "manual"): the module resolver could bypass the read boundary by resolving a package.json main field containing .. segments, allowing a malicious package to read files outside the approved --allow-read scope via req...

CVE-2026-49411

Summary (technical, grounded): CVE-2026-49411 affects Deno’s Node.js compatibility TCP path. Prior to v2.8.0, permission checks for deny-net were performed on the original hostname string before DNS resolution and not re-checked after resolution. This allowed a numeric IP alias (for example 21307...

CVE-2026-49983 Deno: process.loadEnvFile() bypasses env permission checks and mutates process.env with only read access

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, environment access is gated by the env permission. You can deny it with --deny-env, or restrict it to a specific allowlist with --allow-env=FOO,BAR. The expectation is that a program running without env permission cannot...